UN 3258 — Elevated temperature solid, n.o.s., at or above 240°C (464°F)
Placard: Miscellaneous. ERG Guide 171. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 3258 Elevated temperature solid, n.o.s., at or above 240°C (464°F) is assigned to ERG Guide 171 for initial emergency response. Variable solid material transported at temperatures at or above 240°C (464°F). Physical appearance depends on specific substance; typically appears as hot or molten solid material that may glow or emit heat. Verify the exact product from shipping papers and SDS before selecting tactics.
Hazard overview: Primary hazards: a hot Class 9 solid that can cause severe thermal burns, fumes, pressure and splatter hazards. Some may burn but none ignite readily. Containers may explode when heated.
Response guidance: For a UN 3258 incident, isolate the area, keep unauthorized personnel away, stay upwind/uphill and confirm the exact material from shipping papers and SDS. Avoid direct water or foam unless incident command confirms compatibility; use dry agents such as dry chemical, dry sand, lime or soda ash when specified. Follow ERG Guide 171 and local incident command procedures.
UN 3258 Quick Details
Common Hazards of UN 3258
- Some may burn but none ignite readily.
- Containers may explode when heated.
- Some may be transported hot.
- For UN3508, Capacitor, asymmetric, be aware of possible short circuiting as this product is transported.
- Polymeric beads, expandable (UN2211) may evolve flammable vapours.
- Inhalation of material may be harmful.
- Contact may cause burns to skin and eyes.
- Inhalation of Asbestos dust may have a damaging effect on the lungs.
Chemical Identity & Physical Properties
Variable solid material transported at temperatures at or above 240°C (464°F). Physical appearance depends on specific substance; typically appears as hot or molten solid material that may glow or emit heat.
| Also known as | Hot solid materialMolten solidElevated temperature materialHigh temperature solid n.o.s. |
| Appearance | Variable solid material transported at temperatures at or above 240°C (464°F). Physical appearance depends on specific substance; typically appears as hot or molten solid material that may glow or emit heat. |
| Flash Point | Not applicable (elevated temperature solid) |
| Boiling Point | Variable depending on specific material; transported above 240°C (464°F) |
| Vapor Density | Not applicable (solid material) |
| Water Reactivity | Variable; some materials may react with water creating steam or violent reactions when hot. Avoid water contact with hot material. |
Fireground Response Guidance — UN 3258
Extinguishing Media
PPE Requirements
Structural firefighters protective clothing provides limited protection; heat-resistant clothing recommended; SCBA required; maintain safe distance due to extreme heat
Isolation & Evacuation
First Actions for a UN 3258 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and 25 meters (75 feet) for solids.
- For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.
- For non-highlighted materials, increase the initial isolation distance in the downwind direction as needed.
📋 Copy & Share Field Card
UN 3258 — Elevated temperature solid, n.o.s., at oUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.